Milk proteins such as lactoferrin (LF), lysozyme (LZ), lactoperoxidase (LP), immunoglobulin-A (IgA), alpha-lactalbumin, beta-lactoglobulin, alpha-, beta- and kappa-caseins, serum albumin, lipase and others are known to have a number of nutritional and other beneficial effects, particularly for infants. Breast feeding of fresh human milk has traditionally been considered the best means to provide nutrition to an infant. Although all physiological roles of human milk proteins have not yet been elucidated, evidence has been obtained that lysozyme, lactoferrin and other milk proteins control the microflora in the gut of infants (Lönnerdal, 1985). Breast milk has been suggested to contain many immune factors that compensate for the undeveloped defense mechanisms of the gut of infants (Saarinen K M et al., 2000). Several human milk proteins have been demonstrated to have beneficial physiologic effects in infants, particularly in the defense against infection and in the optimization of nutrient uptake.
However, many situations arise where the infant cannot be fed mother's milk and synthetic infant milk formulas are used in the place of breast feeding (Motil K J, 2000). Considerable effort has been made to improve synthetic infant milk formulas in order to closely simulate mother's milk.
The protein and non-protein composition of the human milk and cow milk is described by Kunz et al., 1999. The relative concentrations of milk proteins vary between human and cows' milk. For example, lactoferrin and lysozyme are present in a relatively high amount in human milk but in only low or trace amounts in cow's milk.
In general, synthetic infant formula is prepared using cow's milk that does not closely resemble the protein composition found in human milk. Accordingly, cow's milk based infant formula is typically supplemented with various human milk protein components. Typically, commercial infant formulas based on cow's milk contain approximately of 0.1 mg/mL lactoferrin whereas natural human breast milk contains an average concentration of 1.4 mg/mL. Soy-based infant formulas contain no added lactoferrin.
Although addition of recombinant human milk proteins to infant milk or milk formula has been proposed, e.g., using transgenic cows or by addition of microbially produced human milk proteins to milk or milk formula, these approaches do not overcome the various problems of (i) allergies to cow's milk, (ii) the high cost of recombinant protein production and/or (iii) safety issues related to food products.
It would therefore be desirable to provide a plant-derived infant formula having beneficial levels of one or more proteins normally present in human milk, while largely avoiding costly recombinant protein production techniques and associated safety issues. More generally, it would be desirable to provide a nutritional food extract that may be readily and inexpensively obtained in large quantities, can be delivered by itself, as a nutraceutical or added to processed foods, for supplying one or more human milk proteins beneficial to human health.